The present invention relates to insulators for pipes, and in particular to an insulative insert and protective jacket for pipe elbows.
The use of thermal insulating jackets around outdoor pipes, as for various chemical processes, has become an increasingly popular technique used to reduce energy losses. Such insulation typically comprises hollow cylinders or sleeves of insulative material, for example formed glass fibers, expanded synthetic resins, and foams, such as those known in the trade as Cleotemp and Foamglas. The sleeves are typically formed or split into a pair of semicylindrical halves which are positioned over either side of the pipe and fastened in place. A rigid jacket or cover surrounds the insulative insert to protect the same.
Although this type of insulator functions well for straight pipe sections, it is quite difficult to fit the insulator at angled elbow portions of the pipe, and at other similar locations. For example, heretofore, an insulator was fitted at a 90.degree. ell by cutting off the straight insulative sleeve sections perpendicular to the pipe at a location adjacent to the fitting. This leaves a "throat" area between the pipe ends and elbow legs which must be insulated. Specially shaped sections of insulation are cut and individually fitted over the pipe ends and elbow to fill in the throat area. An improved insulator and method for fabricating the same is described in my copending patent application Ser. No. 148,223, filed May 9, 1980, entitled PIPE INSULATOR AND METHOD FOR MAKING SAME, which is hereby incorporated by reference. A two piece, elbow-shaped jacket, known in the trade as a "stove pipe joint", is then positioned over the insulation to protect the same. Such jackets have a central seam, disposed at a 45.degree. angle to the legs of the jacket, with at least two fasteners through the seam to interconnect the jacket halves.
The manual fitting of the insulator about the pipe ends and the elbow is a particularly difficult and time consuming task which requires the services of a highly skilled pipe insulation mechanic. Further, the 45.degree. seam in the protective jacket is not only difficult to form, but is practically impossible to shape in a manner which will mate precisely with the interior edge of the other elbow leg. As a result, the elbow jacket almost always fits poorly, and is not secure.